Extracorporeal ultrasound is an effective diagnostic alternative to endoscopic ultrasound for gastric submucosal tumours

Background: Although endoscopic ultrasonography (EUS) is the best modality in the diagnosis of gastric submucosal tumours (G-SMT), it is still invasiv e and expensive. We evaluated the usefulness of transabdominal ultrasonogra phy (US) as an alternative to EUS in the assessment and clinical management of G-SMT. Methods: This is a prospective study of 156 successive patients who had been diagnosed with G-SMT by direct endoscopic visualization. For e ach patient, US was performed prior to EUS by an examiner who had not been informed about the site or the size of the patient's G-SMT beforehand. US d iagnoses were compared with those ascertained by EUS. Diagnostic grade by U S was divided into three groups: diagnosed (G-SMT was clearly demonstrated including location, site and type), detected (G-SMT was demonstrable but th e type was not clear) and undetected (G-SMT was not demonstrated by US). Re sults: We found that US can be an alternative to EUS for: 1) diagnosis of e xtramural compression, 2) diagnosis of G-SMT with size > 30 nun in diameter , 3) detection and measurement of the size of a G-SMT from 21 to 30 mm in d iameter, and 4) detection and measurement of the size of a G-SMT at both th e gastric angle and cardia, regardless of the size of the tumour. Overall s ensitivity and specificity for the detection of G-SMT were 82.5% and 100%. respectively. The diagnostic rates of G-SMT in each group were 60.1% (86/14 3) for diagnosed, 22.4% (32/143) for detected and 17.5% (25/143) for undete cted. Approximate 95% (21/22) of G-SMT over 20 mm in diameter were at least detected. and 97% (30/31) of G-SMT over 30 mm in diameter were diagnosed b y US. Conclusion: US can be an alternative method in the assessment of G-SM T, especially in the follow-up of patients already diagnosed.